Mono-n-tertiary-alkylmelamines



Patented Feb. 10, 1953 UNITED STATES PATENT OFFICE MONO-N-TERTIARY-ALKYLMELAMINES Newman M. Eortnick, Philadelphia, Pa., assignor to Rohm & Haas Company, Philadelphia, Pa., a corporation of Delaware No Drawing. Application May 13, 1950, Serial No. 161,900

7 Claims.

This invention relates to a new class of mono- N-alkylmelamines; namely, mono-N-tertiaryalkylmelamines, and to their preparation.

By the process of this invention a tertiary-alkylcyanamide is reacted with dicyandiamide under the conditions described hereinafter to form a mono-N-substituted melamine of which one amino group carries the same tertiary-alkyl group as was present in the tertiary-alkylcyanis a tertiary-alkyl group in which, in turn, R1, R2, and R3 are alkyl groups such as the following groups: Methyl, ethyl, n-propyl, iso-propyl, nbutyl, sec.-butyl, tert.-butyl, tert.-amyl, 2-ethylhexyl, lauryl, and hexadecyl groups, and all isomers of these groups. This invention also includes the substituted melamines of the above general formula wherein R1 and R2 taken together with the tertiary carbon atom, C1, represent an aliphatic, cyclic radical to one and the same carbon atom of which are attached both the secondary amino group, =NH, of the melamine and the alkyl group, R3. That is to say, R1 and R2, in addition to representing individual alkyl groups, when taken together also represent an alkylene group, preferably a polymethylene group, the terminal carbon atoms of which alkylene group are both attached to the tertiary carbon atom, C1, which also carries the alkyl group, R3, and is attached to the secondary amino group, :NH, of the melamine. Examples of such alicyclicsubstituted melamines are the following:

%N\ CHPCHZ mN-o C-N'H-C I l 1H1 J:\CH2 H2 V Ha 1'111,

and

CHzC112 HzN-C o- 7 CH2 l l\ l CH2 Cfiz G C2H5 BIIHI which are made respectively from dicyandiamide and the following tertiary-alkylcyanamides:

CH -CH and CHz-CH:

CH2 C-NHCN OHFOHQ mm The smallest aliphatic radical represented by the characters R1, R2, and R3 above is, of course, the methyl group and the largest is the hexadecyl group since this invention is limited to those monosubstituted melamines which can be made commercially and in which the total number of carbon atoms in the three R-groups is from three, as in the case of 2-tert.-butylamino-4,6- diamino-l,3,5-triazine, to eighteen, as in the case, for example, of 2-tert.-nonadecylamino-4,6 diamino-l,3,5-triazine:

It is to be noted that the groups which are represented by R1, R2, and R3 are not affected by the reaction or the tertiary-alkylcyanamide and dicyandiamide, so that, as a result, the substituted melamines which are produced have the same substituents, R1, R2, and R3, as the alkylcyanamides from which they are made.

The tertiary-alkylcyanamldes from which the new substituted melamines of this invention are prepared are themselves new compounds and they are the subject of another application. Serial No. 161,899, filed May 13, 1950, by this inventor. They are unique compounds in that they are much more stable than other alkylcyanamides and they react readily with dicyandiamide to form the substituted melamines of this invention whereas known monosubstituted cyanamides such as monocyclohexylcyanamide and monometnylcyanamide do not react in a similar manner.

In preparing the mono-N-tertiary-alkylmelamines of this invention, a tertiary-alkylcyanamide is reacted with dicyandiamide at temperatures above 50 C. in the presence of a strongly basic condensing agent. The substituted melamines are obtained in excellent yields in a high state of purity.

While the reaction of dicyandiamide and the tertiary-alkylcyanamide can be carried out at temperatures from 50 C. to 250 0., it is much preferred and recommended that temperatures C. to about C. be employed.

Best results are obtained when the reaction takes place in .solution, preferably at refluxing Preferably an organic liquidis temperature. used which is a solvent for the tertiary-alkylcyanamide and in which substantial amounts of.

dicyandiamide dissolve but which is not a solvent for the substituted melamine which. isproducedh When such a liquid is employed, the. product precipitates from the reaction mixture as itis formed. Many organic liquids are suitable and the following list is merely illustrative of those which are most readily available andisatisfactory: Alcohols, particularly the lower al- I kanols containing up to carbon atoms. such as.

methanol, the butanols, octanols, and decanols; esters containing up to a total of 12 carbon atoms such'asbutyl acetate; ketones'containing 'up to 12 carbon atoms such asmethylhexyl ketone; nitrobenzenes; nitroparaffins such as nitroethane; dioxane; alkyl ethers of polyglycols such as the butyl ether of diethylene glycol. Hydrocarbons, particularly aromatic hydrocarbons typj ified by toluene, may be usedas diluents for the above solvents. In fact, the reaction takes place in the absence of solvents but always with the production of a contaminated and hard product which requires purification; The reaction, of course; can be carried out under super-atmos pheric pressure;

A" strongly alkaline condensingagentis neces- The alkaline condensing-agentisused. to the extent-of 0.1 to 50 mole per cent-based on the number: of moles of dicyandiamide andtertiaryalkylcyanamide.

The alkali metals Higher amounts .can be. used but there-appears to be no. advantagein: doing.

so.- Inflfact, amuch preferred. ratiois- 1- to 20.mole

per cent.

The process of. this invention is illustrated; by the followingexampless.

Example .1'

Amixtureof 38.5 parts (0.25 mole). of.dimeth.-,. ylneopentylcarbinylcyanamide, 21 parts (0.25 mole) of dicyandiamide, 40 parts of butanol, and 1.4 parts of powdered potassium hydroxide was stirred and refluxed for two hours at which time asecond portion of 1.4 partsof powdered potas-.

sium' hydroxide was added and the refluxing was.

continued for two more hours.. Themixturewas cooled and diluted with 50. par ts,of methanol and-allowed to stand overnight. The precipitate which formed wasfiltered oif, washed .with'250 parts. of boiling. .water, and .dried.. Thedried product. (25 parts) was :then. crystallized from. It. had a-melting point of 160-162 C. and its analysis corresponded to:that

ethylene dichloride.

of a substituted melamine havingthe formula:

4 Example-2..

This procedurewas a" modification of that described in Example 1.

A mixture of 38.5 parts of dimethylneopentylcarbinylcyanamide, 25 parts of dicyandiamide, parts of n propanol, and 1.4 parts of powdered potassium hydroxide was stirred and refluxed for twohours,.at whichtime 1.4 parts of potassium hydroxidewas added and the reaction mixture was again refluxed for two more hours after which a third portion (1.4 parts) of powdered potassium hydroxide was added and the reaction continued. for a final period of two hours. On cooling, a precipitate settled out of the reaction mixture and thismaterial was filtered off, washed with hot water, and recrystallized from. ethylene dichloride. A 68% yield of very-pure produch was obtained which had a meltingpoint of 161 C. and which contained, on -analysis,.35.4%-. nitrogen against a-calculated value of 35.3 .-ni-'- trogen-content in .the substituted melaminehav ingthe formula setforth in Example 1.

Example 3 i The procedure of Example 1 was followed with one exception; namely, that mono-terti-b'utylcyanamide (24.5 parts) was used in place of the dimethylneopentylcarbinylcyanamide. A crystalline solid melting at 156-158 0. was obtained in an 82% yield based on the cyanamide. The following composition was confirmed by analysis:

1. 1-methylcyclohexylcyanamide -1, having the formula GHQ-CH5 o 3 o-NHoN.--

was reacted with' dicyandiamide in the ratio.ofji.. one mole of this cyanamide to 1.2"molesof .di-

cyandiamide in the presence .of I10 mole percent; of 'solid sodium hydroxide and dissolved .in.b'ue.

tanol. Thus, 138' parts of l-methylcycloliexyle} cya'namide-l, 100.8"parts of dicyandiamide}. and L 8 parts of sodium hydroxide weremixedin 300.". parts of butanol at'room temperature. This mix-r ture was heated in 30- minutes to refluxing;tem-.-.

perature and was thereafter. refluxed for six, hours. The mixture was then stripp'edpf bu.-

tanol under a reduced pressure of 10 mm.,a'ndJ. the residue was recrystallized from ethylene dichloride. The product, obtained in an amount. equal to a 72% yield based on the tertiary cyanamide, gave ananalysis which corresponded very closely to that ofthe compound Example 5 diethylcarbinylcyanamide) was reacted with the HzN-C I l /IQI C2115 o 11TH:

Example 6 When the procedure of Example 1 was followed in an effort to react dicyandiamide with mono-nbutylcyanamide in equimolar amounts, no monon-butylmelamine was obtained. Likewise, both mono-methylcyanamide and mono-cyclohexylcyanamide failed to react with dicyandiamide to produce respectively mono-methylmelamine and mono-cyclohexylmelamine by the procedure of Example 2.

On the other hand, the procedure of Example 2 can be employed consistently for the production of mono-N-tertiary-alkylmelamines in yields above 60% by reacting dicyandiamide with the tertiary-alkylcyanamides described above. The resultant substituted melamines carrying the tertiary aliphatic group are eminently suited for the production of thermosetting resins for use in textile-finishes, surface-coatings and adhesives by reaction with aldehydes, particularly with formaldehyde. Such resins are characterized by having greater flexibility than those made from unmodified melamine, by being definitely more soluble in organic solvents, and by having greater compatibility with alkyd resins.

I claim:

1. A compound of the formula 2. A process for the production of mono-substituted melamines having the general formula in which represents a tertiary alkyl radical wherein R1, R2, and R3 are alkyl groups and in addition R1 and R2 taken together with the tertiary atom, C1, represent a cyclic aliphatic radical which carries the alkyl substituent, R3, on the same carbon atom which is joined to the secondary amino group, =NH, the total number of carbon atoms in the groups represented by R1, R2, and R3 totalling three to eighteen, which process comprises reacting at a temperature of 50 to 250 C., in the 6 presence of a strongly alkaline agent, one mole of dicyandiamide and one mole of a tertiary:- alkyl-cyanamide having the general formula R1 Rz+ -NHCN in which R1, R2, and R3 are identical with the same characters described above.

3. A process for the production of mono-substituted melamines having the general formula in which represents a tertiary-alkyl radical wherein R1, R2, and Rs are alkyl groups and in addition R1 and R2 taken together with the tertiary atom, C1, represent a cyclic aliphatic radical which carries the aikyl substituent, Rs, on the same carbon atom which is joined to the secondary amino group, :NH, the total number of carbon atoms in the groups represented by R1, R2, and R3 totalling three to eighteen, which process comprises reacting at a temperature of to 0., in the presence of a strongly alkaline agent, one mole of dicyandiamide and one mole of a tertiary-alkylcyanamide having the general formula R (|3 NHCN in which R1, R2, and R3 are identical with the same characters described above, the reaction being carried out in an organic liquid which is a solvent for said tertiary-alkylcyanamide and is a non-solvent for said substituted melamine, and thereafter separating said substituted melamine.

4. A process for the production of the substituted melamine having the general formula I NH,

([f-N-Cf-C 81117 N CzHs which comprises reacting at a temperature of 80 to 150 C., in the presence of a strongly alkaline agent, one mole of dicyandiamide and one mole 6. A process for the production of the substitfitdimemmfiiihavifigwh gnerallformumfin whichicomprises reacting at a temperature of 80 to;150?-C., in;the presence of a strongly alkaline.

f; flj m; agent, one mole of dicyandiamide and one mole; C-NYG.- V 911w of the tertiary-alkylcyanamide having the fort {1 p g mula (CH3)3CNHCN.

NEWMAN M BORTNICK. ca. CHsa llfH: 1 REFERENCES CITED which comprises reacting am; temperature of 80 15 The following references are of record in the to 150 C., in the presence of a strongly alkaline file of this patent: 7

agent. one mole of dicyandiamide and one mole UNITED STATESWPATENTS of the tertiary-alkylcyanamide having thewfors Niimben. Name," Date mum 23311570.; Eiicks Oct..12,19f43" TL 2361,8231 DAle1io Oct. 31 19:44, CQ FOREIGN PATENTS CHVC CH? Number. Country Date 7*. A-*proc'ess*f0rthe-productwmof'thesubsti"25" 238*,261" Switzerland October 1945 tilted-melaminehaving the general-fbrmula 233,253 Switzerland October 1945' 

1. A COMPOUND OF THE FORMULA
 2. A PROCESS FOR THE PRODUCTION OF MONO-SUBSTITUTED MELAMINES HAVING THE GENERAL FORMULA 